Update changelog

Author: thecrypticace

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - _Experimental_: Add `@container-size` utility ([#18901](https://github.com/tailwindlabs/tailwindcss/pull/18901))
 
+### Changed
+
+- Improve canonicalization for `& > :pseudo` and `& :pseudo` arbitrary variants ([#19178](https://github.com/tailwindlabs/tailwindcss/pull/19178))
+
 ### Fixed
 
 - Discard candidates with an empty data type ([#19172](https://github.com/tailwindlabs/tailwindcss/pull/19172))